1. Field of the Invention
This invention relates generally to a locking mechanism for telescoping extendable pole segments, and more particularly to an improved cam and cam follower arrangement which, upon a quarter turn of one pole segment relative to the other, with only a modest force, the two pole segments become rigidly locked together against relative longitudinal displacement.
2. Discussion of the Prior Art
The present invention is an improvement over the pole locking mechanism described in my earlier U.S. Pat. No. 5,011,319. The pole locking mechanism described in that patent includes a solid (non-tubular) cam fastened to the end of the inner telescoping pole segment where the cam member includes a pair of lobes for cooperating with an arcuate recess of a particular geometry formed in an inner surface of a pair of surrounding cam follower segments. Because the cam member and the plug portion thereof used to affix it to the end of the inner telescoping tube segment is a solid (non-tubular) piece, it is impossible with that design to permit objects of any type to traverse the lumens of the telescoping tube segments. Thus, for example, if the telescoping tubes form the stand for lighting or sound systems used in stage presentations, with a pole lock of my prior art design, it was necessary that the wiring be exterior to the telescoping poles comprising the elongated stand. Moreover, because the lock assembly fit with a close tolerance between itself and the segments of the telescoping poles with which it interfaced, a pneumatic resistance has been encountered when extending and contracting the pole segments in some applications.